diff mbox series

[-rcu/kcsan,06/23] kcsan, kbuild: Add option for barrier instrumentation only

Message ID 20211005105905.1994700-7-elver@google.com (mailing list archive)
State New
Headers show
Series kcsan: Support detecting a subset of missing memory barriers | expand

Commit Message

Marco Elver Oct. 5, 2021, 10:58 a.m. UTC 
Source files that disable KCSAN via KCSAN_SANITIZE := n, remove all
instrumentation, including explicit barrier instrumentation. With
instrumentation for memory barriers, in few places it is required to
enable just the explicit instrumentation for memory barriers to avoid
false positives.

Providing the Makefile variable KCSAN_INSTRUMENT_BARRIERS_obj.o or
KCSAN_INSTRUMENT_BARRIERS (for all files) set to 'y' only enables the
explicit barrier instrumentation.

Signed-off-by: Marco Elver <elver@google.com>
---
 scripts/Makefile.lib | 5 +++++
 1 file changed, 5 insertions(+)
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Patch

diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 54582673fc1a..2118f63b2bc5 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -182,6 +182,11 @@  ifeq ($(CONFIG_KCSAN),y)
 _c_flags += $(if $(patsubst n%,, \
 	$(KCSAN_SANITIZE_$(basetarget).o)$(KCSAN_SANITIZE)y), \
 	$(CFLAGS_KCSAN))
+# Some uninstrumented files provide implied barriers required to avoid false
+# positives: set KCSAN_INSTRUMENT_BARRIERS for barrier instrumentation only.
+_c_flags += $(if $(patsubst n%,, \
+	$(KCSAN_INSTRUMENT_BARRIERS_$(basetarget).o)$(KCSAN_INSTRUMENT_BARRIERS)n), \
+	-D__KCSAN_INSTRUMENT_BARRIERS__)
 endif
 
 # $(srctree)/$(src) for including checkin headers from generated source files